title: Arrestin-dependent but G-protein coupled receptor kinase-independent uncoupling of D2-dopamine receptors.
abstract: We reconstituted D2 like dopamine receptor (D2R) and the delta opioid receptor (DOR) coupling to G-protein gated inwardly rectifying potassium channels (K(ir)3) and directly compared the effects of co-expression of G-protein coupled receptor kinase (GRK) and arrestin on agonist-dependent desensitization of the receptor response. We found, as described previously, that co-expression of a GRK and an arrestin synergistically increased the rate of agonist-dependent desensitization of DOR. In contrast, only arrestin expression was required to produce desensitization of D2R responses. Furthermore, arrestin-dependent GRK-independent desensitization of D2R-K(ir)3 coupling could be transferred to DOR by substituting the third cytoplasmic loop of DOR with that of D2R. The arrestin-dependent GRK-independent desensitization of D2R desensitization was inhibited by staurosporine treatment, and blocked by alanine substitution of putative protein kinase C phosphorylation sites in the third cytoplasmic loop of D2R. Finally, the D2R construct in which putative protein kinase C phosphorylation sites were mutated did not undergo significant agonist-dependent desensitization even after GRK co-expression, suggesting that GRK phosphorylation of D2R does not play an important role in uncoupling of the receptor.
authors.affiliation: Department of Biomedical and Pharmacological Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island, USA.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Celver
authors.forename: Meenakshi
authors.initials: M
authors.lastname: Sharma
authors.forename: Vaidehi
authors.initials: V
authors.lastname: Thanawala
authors.forename: J
authors.initials: J
authors.lastname: Christopher Octeau
authors.forename: Abraham
authors.initials: A
authors.lastname: Kovoor
mesh_terms: D000818:Animals; D019393:Arrestin / Q000502:physiology*; D019390:Arrestins / Q000502:physiology; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000378:metabolism; D018076:DNA, Complementary / Q000096:biosynthesis / Q000235:genetics; D055724:Electrophysiological Phenomena; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D054768:G-Protein-Coupled Receptor Kinases / Q000378:metabolism*; D006801:Humans; D009865:Oocytes / Q000378:metabolism; D018075:RNA, Complementary / Q000096:biosynthesis / Q000235:genetics; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D019311:Staurosporine / Q000494:pharmacology; D014981:Xenopus; D000071557:beta-Arrestins
chemical_list: D019393:Arrestin; D019390:Arrestins; D018076:DNA, Complementary; D004791:Enzyme Inhibitors; D018075:RNA, Complementary; D017448:Receptors, Dopamine D2; D000071557:beta-Arrestins; D054768:G-Protein-Coupled Receptor Kinases; D019311:Staurosporine
keywords: D2 dopamine receptor; G-protein coupled receptor kinase; arrestin; desensitization; protein kinase C; uncoupling